The U.S. Chamber of Commerce announced Monday that Mexico has officially been invited to enter into discussions over an emerging free-trade pact after being left out of the initial dialogue.

The trade pact, called the Trans-Pacific Partnership, includes Australia, Brunei, Chile, Malaysia, New Zealand, Peru, Singapore, Vietnam and the U.S. The partnership’s mission is to “enhance trade and investment among the TPP partner countries, promote innovation, economic growth and development, and support the creation and retention of jobs,” according to the office of Ron Kirk, the U.S. trade representative and former Dallas mayor.

The announcement was made during the commencement of this week’s G20 summit in Los Cabos, Baja California Sur, and comes less than two months after several Republican and Democratic members of Texas’ congressional delegation wrote to Kirk urging him to include Mexico, which surpassed China last month to become the country’s second-largest trade partner after Canada. Mexico remains Texas’ No. 1 trade partner, and the ports of Laredo, El Paso and Houston remain among Mexico’s top five trading partners.

“As our neighbor and second-largest export market, Mexico’s participation will help ensure the TPP becomes an engine for economic growth,” Thomas Donohue, the president and CEO of the U.S. Chamber of Commerce, said in a statement. “The U.S. and Mexican economies are already closely integrated, with more than one-third of the content of Mexico’s exports made in the U.S., so this has the potential to be a huge win for American companies and workers.”

But not all have applauded the move. Last month during meetings in Dallas over the pact, the AFL-CIO held demonstrations to protest the negotiations. The union has been critical of previous free-trade pacts, claiming that they lead to fewer jobs for U.S. workers and drive down wages. And it argues that the discussions involving the pact have brought secret negotiations to a new level.

“You don’t have to be a critic of ‘free trade’ to know that the level of secrecy of negotiations is dangerous,” Becky Moeller, the president of the Texas AFL-CIO, said in the coalition’s May newsletter. “To say that the TPP at this moment is a pig in a poke is to do dishonor to the poke industry.”

But supporters here will likely point to Texas’ burgeoning trade relationship with Mexico, which has increased despite a global recession and Mexico’s ongoing drug war, which has claimed more than 50,000 lives since 2006.

In 2011 Mexico’s exports to the U.S. increased 20.95 percent, and imports rose 14.57 percent. The Laredo trade district accounts for about $207 billion of that trade, followed by El Paso at $78.1 billion and Houston with $31.4 billion, according to U.S. census data analyzed by WorldCity, which tracks global trade patterns.

JULIAN AGUILAR reports for The Texas Tribune where this story was originally published. It is reprinted here through a news partnership between the Tribune and the San Marcos Mercury.